1. Field of the Invention
The present invention relates generally to batteries and more specifically to a multiple battery arrangement that powers a device.
2. Description of the Related Art
Battery-powered portable electronic devices have become increasingly popular due to their light weight and compactness. These devices, such as cellular radiotelephones and laptop computers, are typically equipped with only a single main battery and, thus, their operational time is short. Also, the operation of devices must be interrupted to replace the single main battery. Such interruptions can come at undesirable times--during a cellular radiotelephone call or while processing computer data--and lead to undesirable results--a dropped call or lost data.
In response to these shortcomings, some portable electronic devices have been equipped with an auxiliary battery. These portable electronic devices automatically switch between the main and auxiliary batteries to avoid interruption in operation. For example, as the main battery becomes depleted, the device switches to the auxiliary battery. The main battery can then be replaced. Once replaced, the device switches back to the main battery when the auxiliary becomes depleted, and so on. One envisions perpetual operation of the portable electronic device if such replacement of depleted battery packs is maintained. Unfortunately, such devices do not permit the user to replace the in-use battery without interrupting the operation of the device. Replacement is limited to the depleted battery after switch over occurs.
Also, additional hardware is necessary to effectuate switching of a multiple battery arrangement. For example, one such prior art device requires an additional voltage detector, an additional flip-flop circuit, and numerous additional switches to accommodate the auxiliary battery. This increases the cost, the complexity, and the size of the device.
What is needed therefore is a more economical apparatus and method for discharging a multiple battery arrangement in a manner that allows for uninterrupted continuous operation of a device.